McALESTER, Okla. (AP) — Two Oklahoma death row inmates whose executions were delayed while they challenged the secrecy behind the state’s lethal injection protocol are scheduled to die Tuesday in the state’s first double execution in nearly 80 years.

Clayton Lockett and Charles Warner will receive a new lethal injection formula that includes the sedative midazolam as the first in a three-drug combination.

Madeline Cohen, Warner’s attorney, said the inmates have exhausted all of their appeals.

“We are really out of legal options, because the challenges that were brought to the execution were brought under state law, and they were decided as a matter of state law,” Cohen said.

It is the first time since 1937 that two men have been executed on the same day in Oklahoma, although it has happened in other states since the death penalty was reinstated in the U.S. in 1976. The last double execution was in Texas in 2000.

Lockett, 38, is scheduled to die at 6 p.m. A four-time felon, Lockett was convicted of shooting 19-year-old Stephanie Neiman with a sawed-off shotgun and watching as two accomplices buried her alive in rural Kay County in 1999 after Neiman and a friend arrived at a home the men were robbing.

Warner is scheduled to be put to death two hours later in the same room and on the same gurney. The 46-year-old was convicted of raping and killing his roommate’s 11-month-old daughter in 1997. He has maintained his innocence.

Lockett and Warner had sued the state for refusing to disclose details about the execution drugs, including where Oklahoma obtained them.

The case, filed as a civil matter, placed Oklahoma’s two highest courts at odds and prompted calls for the impeachment of state Supreme Court justices after the court last week issued a rare stay of execution. The high court later dissolved its stay and dismissed the inmates’ claim that they were entitled to know the source of the drugs.

By then, Gov. Mary Fallin had weighed into the matter by issuing a stay of execution of her own — a one-week delay in Lockett’s execution that resulted in both men being scheduled to die on the same day.

“Our goal is to make sure justice is served,” Fallin said Tuesday. “The courts have ruled, and there is no doubt as to the guilt of the perpetrators of the crimes.”

Warner was served a final meal Tuesday of 20 boneless chicken wings, potato wedges, cole slaw, two fruit cocktail cups and a 20-ounce soda.

Lockett’s request of steak, shrimp, a large baked potato and a Kentucky Bourbon pecan pie was denied because it exceeded the $15 limit, and he declined a separate offer from the warden for a dinner from Western Sizzlin’, prison officials said.